While chatting with my online buddy and fellow firearms enthusiast pdb this afternoon, I was suddenly struck by my annual Good Idea. I was beginning to worry, since it’s nearly November and, while I’d had (and acted on) plenty of Bad and Really Bad Ideas, the Good Idea was proving elusive. Oh, me of little faith…

So what’s the great idea? A trigger-pull gauge that cost me $0 and seems to be reasonably accurate and quite repeatable.

Part the First: Gathering the materials

1 – empty 2-liter pop bottle (here in the Midwest, it’s pop, not soda, dammit)
1 – regular wire coathanger
1 – 18″ strip of duct tape

Part the Second: Assembling the test apparatus

Use the duct tape to attach the 2-liter to the bottom of the coathanger, horizontally. Slightly straighten out the hook of the coathanger so it’s easier to fit through the trigger guard. That’s it. We’re not building a Saturn V here, kids.

Part the Third: Measure the damn thing already

Fill up the bottle. Put the cap on (Do I really need to spell that part out?). Clear the gun. Cock it, if necessary. Hold the gun, pointed straight up, and hang the coathanger from the middle of the trigger.

A liter of water weighs 2.2 lbs. Throw in an ounce or two for the bottle, hanger, and tape. If the trigger doesn’t trip on a full 2-liter bottle, your trigger is over 4.5 lbs or so. Get a bigger bottle and try again, or just head for the gunsmith. If the trigger DOES trip, you can pour water out of the bottle, a little at a time, and re-test until the trigger holds. Then figure out how much water is in the bottle and multiply by 2.2 lbs. Yeah, I know, I didn’t list a calculator on the materials list. Oops.

Actually, since most factory triggers are going to be well over 4.5 lbs these days, the $0 trigger pull gauge would be considerably more versatile with a gallon jug in place of the 2-liter bottle. However, I’m profoundly lazy and I didn’t happen to have a gallon jug handy. Such is life. For reference, a gallon of water weighs 8.35 lbs.

Now, I’m not using distilled water at standard temperature and pressure, and I don’t know the exact weight of the rest of the test apparatus. Big deal. This method isn’t going to produce an answer to six significant figures. Still, it’s quick way to get a pretty good idea of your piece’s pull weight, and it’s hard to beat the price.